By James Mackenzie and Timour Azhari JERUSALEM/BEIRUT (Reuters) -Israel will press on with discussions on ceasefire proposals for Lebanon in the days ahead, Prime Minister Benjamin Netanyahu said on Friday,

The United States is working urgently on a plan to mediate a ceasefire between Israel and Hezbollah, according to three sources familiar with the matter, as officials eye with deepening concern the prospects of a widening conflict.

Israeli airstrikes have claimed over 630 lives in Lebanon since a further 72 people are reported by the nation's Health Ministry to have been killed in attacks on Wednesday, resulting in emergency talks at this week's U.N. General Assembly in New York.